Monolithic Power Systems Inc. MPQ8903DJ-3.3-LF-P

Overview

MPQ8903DJ-3.3-LF-P from Monolithic Power Systems is a fixed-output 3.3V, 150mA industrial-grade low-dropout linear regulator operating from 2.7V to 6.5V input, delivering ±2% output accuracy with 100mV dropout at 100mA, thermal shutdown protection, and stable operation with low-ESR ceramic capacitors. It powers noise-sensitive analog blocks in compact portable electronics.

For engineers reviewing the MPQ8903DJ-3.3-LF-P datasheet, MPQ8903DJ-3.3-LF-P pinout, MPQ8903DJ-3.3-LF-P application, or MPQ8903DJ-3.3-LF-P equivalent, key selection criteria include guaranteed –40°C to +85°C operation, TSOT23-5 package footprint compatibility, fixed 3.3V output without external feedback, and thermal protection behavior under sustained load.

Technical Context

The MPQ8903DJ-3.3-LF-P uses a PMOS pass transistor architecture enabling low dropout voltage and inherent reverse-polarity protection. Its internal 1.222V bandgap reference feeds a precision error amplifier that regulates output by adjusting the pass device's conduction.

It integrates an enable-controlled startup sequence (EN pin active-high), thermal shutdown triggered at 155°C with 30°C hysteresis, and operates stably with 1µF–10µF X5R/X7R ceramic output capacitors-eliminating need for electrolytic or tantalum types.

Key Specifications

Pinout & Package

MPQ8903DJ-3.3-LF-P is housed in a 5-pin TSOT23 package (2.9mm × 1.6mm × 0.85mm height) with exposed pad for thermal enhancement. Pin 1 is IN, Pin 2 is GND, Pin 3 is EN, Pin 4 is FB, Pin 5 is OUT.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with MCP1703T-3302E/MB and TLC7603CD5, MPQ8903DJ-3.3-LF-P delivers superior dropout performance (100mV vs. ≥300mV) in the same TSOT23-5 footprint, enabling longer runtime from marginal input voltages while maintaining industrial temperature compliance and ultra-low shutdown current.

Availability

MPQ8903DJ-3.3-LF-P is available at Aetrix Electronics and suitable for 802.11 PC cards, mobile handset PLL power, and audio codec power applications requiring stable component supply, guaranteed industrial temperature operation, and RoHS-compliant packaging.

Supply support for MPQ8903DJ-3.3-LF-P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, headquartered in Kirkland, Washington, with global design and support centers.

The MPQ8903 belongs to MPS's industrial-grade linear regulator product line, engineered specifically for noise-sensitive analog subsystems in portable and harsh-environment electronics where precision, thermal robustness, and small-footprint integration are mandatory.

FAQ

Can MPQ8903DJ-3.3-LF-P be used with ceramic output capacitors smaller than 1µF?

No. The datasheet specifies minimum 1µF X5R/X7R ceramic capacitance on the OUT pin for guaranteed stability across –40°C to +85°C. Using <1µF risks oscillation, especially under light loads or elevated temperatures, due to insufficient phase margin in the control loop.

Is the FB pin left floating in the fixed 3.3V version?

Yes. For MPQ8903DJ-3.3-LF-P, the FB pin is internally connected to the fixed 3.3V divider and must remain unconnected (no external components). Connecting external resistors or capacitors to FB will disrupt regulation and may cause output inaccuracy or instability.

What is the maximum allowable power dissipation at 85°C ambient?

At TA = +85°C, maximum continuous power dissipation is 300mW, calculated as PD(MAX) = (TJ(MAX) − TA)/θJA = (150°C − 85°C)/220°C/W. Exceeding this causes thermal shutdown activation, confirmed by the 155°C trip point and 30°C hysteresis.

Does EN pin require a pull-up resistor for automatic startup?

No. The EN pin can be directly tied to IN (Pin 1) for automatic turn-on at power-up. No external pull-up is needed because the internal EN threshold is 1.5V (min), and IN ≥2.7V meets this requirement across the full operating range.

How does the 100kΩ total resistance limit apply to the feedback network?

The 100kΩ limit applies only when converting to adjustable mode using external R1/R2. In MPQ8903DJ-3.3-LF-P (fixed version), FB is NC and the limit is irrelevant. For adjustable variants, exceeding 100kΩ increases susceptibility to noise and degrades regulation accuracy due to leakage current effects.

Is the TSOT23-5 package lead-free and RoHS compliant?

Yes. The "-LF" suffix in MPQ8903DJ-3.3-LF-P explicitly denotes lead-free, RoHS-compliant construction per EU Directive 2011/65/EU, including matte-tin lead finish and halogen-free molding compound.

What is the typical ground current (IGND) at 150mA load and 5V input?

Typical ground current is 125mA at IOUT = 150mA and VIN = 5V, measured per Figure 4 in the datasheet. This value includes both quiescent current and pass transistor drive current, confirming high efficiency (>95% at nominal conditions) for a linear regulator.